1. Field of the Invention
This invention relates to a mechanism for scraping off deposit material from the surface of a moving body such as a rotary drum, an endless filter cloth belt or the like.
2. Description of the Prior Art
As disclosed, for example, in U.S. Pat. Nos. 3,869,389; 3,699,881; 3,601,039; 3,478,888 and 1,415,859, conventional scrapers are provided with a scraping member which is fixedly or detachably attached to a support member to scrape off sludge or other deposit of processed material from the surface of a rotary drum or an endless filter cloth belt, keeping a constant distance from the surface of the drum or belt.
However, in a case where the processed material contains a large amount of foreign matter such as fiber, hair, paper, cloth or the like, a difficulty is often encountered in that the efficiency of the scraping operation is lowered considerably by the foreign matter which entangles around the blade of the scraper, forming space between the scraper blade and the surface of the rotary drum or the endless filter cloth belt.
For instance, in the case of a belt press type dehydrator which is employed for the treatment of sludge in a waste water treating process, there occurs the necessity of removing with a scraper the sludge which deposits on the surface of a filter cloth belt as a result of a dehydrating treatment. On such an occasion, the more the foreign material entangles around the scraper blade, the more the latter is spaced away from the surface of the filter cloth belt, inviting clogging of the filter cloth belt with the residual deposits which cause degradations in the operational efficiency of the dehydrator.